This invention relates generally to loading dock shelters and is particularly directed to a bottom seal for a loading dock shelter of the L-shaped pad type.
Loading dock shelters having an L-pad are used to provide a seal between a building wall and a vehicle such as a truck which is being loaded or unloaded through an open doorway in the wall. These L-pad structures generally include a pair of L-shaped pads positioned adjacent to facing lateral edges of the doorway in combination with a head seal disposed over the doorway. Each of the L-pads includes a body portion extending generally perpendicularly outward from the wall and a leg portion extending from the distal end of the body portion generally parallel to the wall and inwardly toward the doorway. Each of the L-pads is comprised of a compressible, resilient material such that when its leg portion is engaged and deflected inwardly by a truck, the L-pad flexes inwardly while remaining in contact with an aft lateral edge of the truck. The head pad prevents the movement of air through the doorway above the truck, while either a lower bumper pad or dock leveler extending outward from the loading dock blocks movement of air through the doorway from beneath the truck. However, gaps on each side of the truck adjacent lower portions of each of the L-pads allow the movement of air through the doorway during loading/unloading of a truck using the dock shelter. This air movement exposes the inside of the building into or out of which goods are either being off-loaded from or on-loaded to the truck to the outside elements and is, of course, undesirable.
Prior attempts to seal off these gaps have made use of a flat, wedge shaped element coupled to a lower, inner edge of the L-pad. These wedge shaped elements are either comprised of a compressible, resilient material such as foam or a wear resistant, high strength flexible fabric. The foam-type wedge seal is intended to serve as a gusset behind the front face of the L-pad and to lend support to the pad. Unfortunately, the flat, wedge-like shape of these seals requires the exertion of large compressive forces to displace the L-pad so that it is in sealed conformance with the aft edge of a truck. In addition, these prior art compressible bottom seals provide support only for that portion of the L-pad with which it is in contact. Consequently, the application of large compressive forces for extended periods of time to those portions of the L-pad not adjacent to the gusset result in those portions of the L-pad becoming permanently mishappen. Once a dock shelter pad takes an irregular "set", its ability to form a seal with an edge of the truck is substantially impaired. Moreover, these prior art bottom seals do not completely fill the gap adjacent the lower edge of the L-pad and thus did not adequately seal the lower portion of the truck-wall interface. Finally, these prior art seals became misshapen not only from the large compressive forces applied by a truck using the dock seal, but also because the bottom seal tends to sag and to assume a curved shape. This further reduces the capability of the bottom seal to fill the gap adjacent to the lower, lateral edge of the rear of the truck.
The present invention overcomes the aforementioned limitations of the prior art by providing a pyramidal-shaped bottom seal for an L-pad dock shelter which remains in intimate contact with the L-pad and completely fills the gap adjacent to the lower edge of the L-pad regardless of the extent to which the pad and the bottom seal are compressed by a truck using the dock shelter. The upwardly tapered shape of the bottom seal reduces the compressive force which must be applied to the L-pad for compressive sealing with an aft edge of the truck, and biases the L-pad to its original shape when not in use. The pyramidal bottom seal is securely attached to the inner edge of the L-pad and includes a compressible, resilient foam core which is easily collapsed, but returns to its original shape almost immediately because of the "breathing" effect of the bottom seal's full mesh lower surface.